Tabletting machines commonly include a so-called rotary press which is accommodated inside a casing. The casing normally is tightly sealed from the outside via side walls and/or window-type flaps to prevent product dust, which inevitably will develop during operation, from leaking to the outside. If more dust develops it will be exhausted permanently. The feed of the powdered material and the discharge of the tablets are performed into and out of the casing, respectively, via ducts.
Tablets which contain concentrated or toxic substances require that the tablets be removed from the interior of the tabletting machine casing for further treatment and packaging with operators not getting into contact with them or being exposed to detrimental environmental effects. If strict sterility requirements are made it should be possible to exchange components of the rotary press in a way to prevent the operator from getting into contact with those components or the environment from getting contaminated. Hence, it is known to provide so-called transfer locks (e.g. RTP). They have a flap which is pivotally supported to be swung inwardly in the area of an aperture in a casing wall and normally closes the aperture tightly. To this end, the inside of the casing wall has mounted thereon a locking device which has to be unlocked first for the flap to be opened. Unlocking is done from inside. An access for a glove to enable unlocking is provided in the casing wall near the aperture.
A lock channel, e.g. a piece of pipe or a flexible tube of a major diameter, has a counter-profile at one end that interacts with a connection profile around the aperture in the casing wall. Further, this end has attached thereto a second flap which interacts with a driver profile of the first flap when the connection profile and counter-profile are brought into engagement. Now, if the first flap is unlocked from inside it becomes possible to swing the second flap into the interior of the press casing by means of the first one. This creates a sealed passage into the casing interior from the lock channel. The access for a glove helps in removing an article from or inserting the article into the outwardly closed lock channel.
The connection profile and counter-profile mostly define a bayonet joint. For a creation of the connection profile in the casing wall, it is known to form metallic flanges from high-grade steel and screw them together on the two sides of the aperture. Manufacturing and mounting such components is troublesome and requires great care with regard to tightness and sterility.
It is the object of the invention to provide a transfer lock for a tabletting plant in which the assembly effort is reduced and improved tightness is achieved.